Classifier



April-25, 1950 G. D. FENTON CLASSIFIER 5 Sheets-Sheet 1 Filed June 28, 1946 fi w llllllllllllllllljill Illl.

"1720675507": 635mm? 00/1 40 FE/VTU/K April 25, 1950 G. D. FENTCN 2,505,283

CLASSIFIER Filed June 28, 1946 5 Sheets-Sheet 2 FIG. 2.

April 25, 1950 an. FENTQN CLASSIFIER Filed June 28, '1946 5 Sheets-Sheet 3 muff/Wag G. D. FENTON April 25, 1950 CLASSIFIER 5 Sheets-Sheet 4 Jiled June 28, 1946 FIELB- 1110mm.- 550E615 flo/mm E A 70m,

G. D. FENTON April 25, 1950 CLASSIFIER 5 Sheets-Sheet 5 .--Filed June 28, 1946 0750/96: fio/wm fZ/vm/M Patented Apr. 25, 1930 CLASSIFIER George Donald Fenton, Worcester, Mass, assignoi' to The American Steel and Wire Company of New Jersey, a corporation of New Jersey Application June 28, 1946, Serial No. 680,216

(or. coc -s2) Claims. 1

This invention relates to a classifier of the type adapted to measure the sizes of articles and to classify them accordingly in an automatic manner, in its specific form the invention providing for automatically classifying coiled springs according to their lengths. This application is a continuation-in-part of application Serial No. 534,144, filed May 4, 1944, which issued as Patent No. 2,409,265, October 15, 1946.

The invention has among its objects the provision of an improved apparatus of the type disclosed and claimed in the above prior application.

Such improvements relate to a removable anvil beneath the coil setting station which may be replaced when worn, a precision means for adjusting the height of the electrodes at the various gauging stations, means for facilitating removal of the springs from the classifying and gauging device at appropriate stations, and an improved control circuit for the device.

The invention will be more readily understood by reference to the accompanying drawings, illustrating a preferred embodiment of the invention, in which:

Figure 1 is a partly sectioned side view;

Figure 2 is a vertical section on the line II--II in Figure 1;

Figure 3 is a top view; Figure 4 is a partly sectioned portion of Figure 3;

Figure 5 is a perspective of details;

Figures 6 and 6 taken together, constitute an enlarged view in side elevation, certain of the parts being partially broken away, of an electrode and its supporting and adjusting means; and

Figure '7 is a schematic view of the control circuit and associated control devices of the apparatus.

As indicated, the present invention is an improvement upon that disclosed and claimed in the prior application, Serial No. 534,144. The device of the present invention is essentially similar to that shown and disclosed in the previous application, but with various parts thereof improved to provide an apparatus which is faster and more accurate in its operation. In the following description there is described a preferred modification of the device embodying the improved adjustable electrode mounting, the wearresisting insert and the rin support under the spring setting plunger, and the improved electrical control circuit for the device.

In the device shown the classifier is provided with a frame i,'mounting a horizontal metal ring 2 having a top annulus providing a horizontal, smooth, flat, metal surface 3 having a series of flush, spaced, metal trap doors provided in the form of slides 4, 5, B, and fitting in radial grooves 8 formed in the surface 3 of the ring 2.

The ring 2 is provided with vertical holes 9 closed by these slides when they are slid radially outwardly, in which directions they are biased by springs ID, the slides having vertical holes H which may be registered with the holes 9 by sliding the slides inwardly against the bias of their springs II], the slides otherwise providing flush continuations of the surface 3 of the ring 2. Each of the slides is provided with its own electric motor for opening it, such motor being in the form of a soft iron plunger l2 working in electric solenoid l3, mounted by the frame I through a bracket [4. The solenoid, upon energization, pulls the plunger l2 against the bias of the spring II] and thus pulls with it the slide to which it is connected so that its hole ll registers with the hole 9 in the bottom of the groove 8 in which the slide is fitted. Preferably the ring 2 and the slides are made of steel and the surface 3 and the top surfaces of the slides, which ride flush with this surface 3, are all hardened by suitable treatment.

A vertical shaft I5 is journaled in the frame I by bearings and its upper end mounts a turntable [6 having a depending flange ll, riding lightly on the surface 3, this turntable providing a plurality of upstanding, spring embracements I8, whereby to mount these embracements so they repetitiously travel over the surface 3 in line with the series of trap doors, the trap door series being arcuate. These spring embracements l8 are provided with bores I9, in which the springs to be classified are placed, whereby the embracements, when moved over the surface 3 by rotation of the turntable I6, slide the springs over this surface 3 in upright positions, with the bottom-spring-ends riding over the trap door series so that opening of any trap door will permit the spring registered therewith to drop through the trap door, the springs being biased against the surface 3 by gravity.

Rotation of the turntable it is effected by rotation of the shaft l5 on which it is mounted, this being done intermittently through a Geneva drive 20, the continuously rotating cam of which is powered by a vertical shaft 2!, journaled by the frame I in bearings, through a friction drive 22, by an electric motor 23 working through a speed reduction gearing 24. The arrangement is such that for each revolution of the shaft 2|,

{of a cone of large included angle.

the intermittent drive 20 turns the shaft l just sufliciently to move the spring embracements l8 from one of the trap doors to the next so that each of the embracements is successively registered over each of the trap doors. Of course, the embracements I8 are located on a circle concentric with shaft l5, and have the same spacing as the trap doors.

Theimproved top-spring-end contactorsile, I8, 80, and 82 are mounted on the horizontal panel 29 spaced above the trap door series by means of columns 30, the arrangement being such that these contactors are over each trap door at spaced positions above the embracement tops at successively lower heights in the direction of travel of the embracements. Thus contactor leds-directly above the trap door 4, contactor .18, is directly above the trap door 5, and so forth, it following that the top-springends of the longest springs will contact the contactor 16, those of the next highest spring will contact the contactor I8, and so forth. Each contactor is made with a bottom .face, as shown more clearly .in Figure 6*, that has a centrallylocated flat portion joined to the side edges by a surface which is a frustum Such configuration of the bottom surfaces of the contactors-makes it unnecessary to lock them in any particularangular position about their axes and insures that they will have the same action with respect to the'top-spri'ng-ends regardless of how they are positioned angularly.

The construction of the contactor mountings will be more readily appreciated by reference-to ,TFi'gur es 6 and 6 in which the mount for contheidevice'by a wire (not shown) connected to flange 86. A further metal washer '99, roughly corresponding in shape to the flange .86, is inter- .posedbetween thel owerinsulating washer 88'and the retaining nut 92 threaded on the lower :end or the barrel. m m

'Ihe contactor i5 is rigidly mounted on the lower end of the adjustable spindle 93 as by being pinned thereto as shown. Such spindle has an axial bore 9 extending completely therethrough .and communicating with the bore 95 through the center of the contactor to permit the discharge of compressed air from the contactor when springs are 'positioned'therebelow, as will be more fully described later. Barrel 8 isprovided with an accurate internal thread, in the upper portion 96, which receives the threaded upper portion 91 of the spindle. Rotation of the spindle thus-allows an accurate axial adjustment of the contactor. Such rotation may be accomplished by means of the thimb1e'98 connected to the upper end of the spindle, thelower portion of such thimble extending over the sleeve 99 which telescopes the barrel 34. The sleeve 99 is provided with graduations to permit the adjustment of the spindle to be read.

The upper end'of the barrel 84 is tapered and threaded at I00, such portion being slotted as shown at [ill to allow it to be sprung inwardly into tight engagement with the threaded-portion of the spindle. Such springing of the upper end of the barrel may be accomplished by rotation of the conically threaded nut Hi2 embracing portion I09, and allows a firm accurate engagement to be maintained between the threads on the barrel and the spindle.

When suitably adjusted, spindle 93 may be locked in position by means of :the nut I03 threaded into a bore rcoaxial of the spindle on the lower end of the barrel. The forward end t0! of the threaded portion I of such nut is conical, as shown, and sets into a correspondingly shaped conical seat in the barrel. Such conical portion is slotted at H19 so that when the nut is'screwed into the barrel the conical forward end thereof J's-sprung into tight engagement with the spindle to lock it in place. For fixing sleeve '99 on barrel as 'a sinuous spring H3 is seated within the longitudinal keyway I! I on the lower end of the barrel, alternate high points of the spring engaging the inner cylindricalsurface of the sleeve.

Generally speeaking, in the operation of the machine the motor '23 intermittently turns the shaft l5 so as to bring each of the embracements successively over'each trap door and beneath each of the top-spring-end contactors, and the latter are connected in each instance with the solenoid I3 of the trap door above which it is positioned, whereby, depending upon their lengths, the varioussprings are dropped through various onesof the trap doors so as "to .be classified into four different length categories. The springs are manually loaded into the embracements 18 prior to the time the embracements start over the various trap doorsand under-the various contactors, the operation being otherwise automatic. For convenience, each trap door delivers the spring it passes to its own delivery tube, these tubes being shown at 34,,135, 736, and 3?, respectively delivering to drawers 3B, '69, and t-l where the springs collect according to their classified lengths. Since some springs may be much too short, the surface '3 of the ring 2 is preferably provided with a vertical hole "42 that is always open andthrough which any spring that reaches 'thishole must drop, the hole 52 alsohaving its spring conveying tube 43 deliveringtoa drawer 44. This hole 12 is spaced from the last ofthe trap door series to effect successive registrations of the various embracements therewith as the embracemerits are intermittently revolved'by the intermittent rotation of the shaft l5.

At the first embracement-stopping position in advance of the-trapfdoor t, the panel29 mounts'a top-spring-end depressor in'theform of a plunger 45 worked by a pneumatic motor of which the cylinder E6 is-shown mounted vertically b the panel '29,'the depressor being biased to an upward, inoperative position by a, spring 4? and the introduction of air to the topendof the cylinder 45 serving to=drive the depressor downwardly so as to engage the top end of each spring, after it-has been placed in the bore 19 of an embracement [8, so as to close the spring more or less and drive itsbottom end into firm-engagement with the surface 3over whichit thereafter slides. The use'of the pneumatic motor has an advantage in-that it providesfor a somewhat retarded returnstroke of the depressor 45, thus eliminating the possibility of sudden release of a seated spring with the consequentpcssibilityof its becoming unseated which-would lead to its inaccurate classification.

Because the ring.2 is subjected to .considerable Wear at the location beneath the depressor, there is provided, as shown in Figure 1, a replaceable insert I04 in the ring atthat place. The insert I04 may be made of hard material, such as sintered tungsten carbide, and is finished so that its top surface lies flush and continuous with the top surface 3 of ring 2. The insert may be inserted through the-bottom of the ring, and retained therein by a shoulder on its bottom end received within a correspondingly shaped seat in the bottom ofthe ring 2. I

The above described structure constitutes only some of the details which permit the classifier to operate accurately at high speeds, another being the manner in which the various contactors are connected with the various solenoids of the various trapdoors, this being done in such a manner that during the earlier portionsof the stops in the intermittent motion of the embracements, the determination is made as to whether a top-springend is in contact with the contactor below which it is registered, and so that subsequent contact during the latter portions of the stops, when there might be spring vibration, will have no effect, such subsequent contact failing to do anythin in the way of opening the trap door beneath the contactor thus subsequently contacted. Then, during the latter portions of the stops, the electric motor working the trap doors is operated to momentarily open the trap doors only in those instances where the springs initially contacted the topspring-end contactors. The manner in which all of this is accomplished will now be described.

The shaft 2|, which is turned continuously by the motor 23, makes one complete rotation for eachpartial rotation of the shaft I5 effected by the Geneva drive 20 and the latter is designed so the shaft 2I turns about 120 for each of the partial rotations of the shaft I 5 required to index the various spring embracements IS with the various trap doors and contactors. The shaft 2I carries cams 48, 49, 50 and 5I working electric switches 52, 53, 54, and 55, this arrangement being such that the switch 52 closes when the shaft 2I has rotated about the 120 terminating the indexing motionit imparts the shaft I5, and opens after the shaft 2I turns about 270. In this connection, is taken as the position of the shaft 2| when it starts to turn the shaft I5 through the Geneva drive 26. The switch 53 also closes at about 120.but it opens at about 210, the switch 54 closes at about 180 and opens at about 372 which means that it opens during about the first 12 of the next cycle, and the switch 55 closes at about 240 and opens at about 360. This timing may be varied somewhat but the general sequence should be followed.

Referring now to the wiring diagram, the motor 23 is powered by the A. C. lines 56 which also power an electric thruster 5! working a three-way, compressed air control valve 56 supplied with compressed air by a pipe 59 and transmitting this air, through its control, by way of a pipe 60 to the top end of the cylinder 46 Working the top-springend depressor 45. Exhaust air from cylinder 46 is delivered from valve 58 through pipe I06 to the manifold I08 where it flows through hoses III] to the adjustable mounts for the contactors. When the thruster 51 is energized it sendsair to the top of the cylinder 46, and when it is deenergized the valve 58 moves to connect the pipe;

acts to aid removalof the springs from the em:

bracements, as described above. Therefore, as each spring embracement I8 registers with the depressor 45 and comes to a stop, the thruster 57 is energized by the switch 52, through lines 6|, so that air is introduced to the top of the cylinder 46, this driving the depressor 45 downwardly so that it operates to perform it function, the switch 52 then opening so that the spring 41 returns the depressor to inoperative position. The switch closes at 120 turn of the shaft 2I and opens when the shaft ZI turns 270, so that the shaft can continue to turn more before it begins to again rotate the shaft I5, this allowing time fo the spring 41 properly to perform its function. The operation is continuous and this means that all of. the embracements beneath the various contactors 16 through 82 are successively loaded with springs which-then have their bottom ends firmly seated on the surface 5.

At rotation of shaft 2I, switch 53 also closes and energizes a relay solenoid 62 via conductors 6| and 63. Energization of said solenoid closes four sets of relay contacts 64. Each of the four electric motors I3, which operate the four slides 4, 5, 6 and I, has an actuating relay which includes a solenoid 66 and two sets of contacts 65 and H2. The circuit for energizing motors I3 and solenoids 66 includes conductors H6 and H8 which are connected to a source of low voltage potential. One terminal of each solenoid 66 is connected to conductor IIB via a conductor I20 and switch 54 (now open). The other terminal of each solenoid 66 is connected to one of relay contacts 64 via a conductor 61. Each, of said relay contacts is also connected to one of; the top-spring-end contactors I6, I8, 80 and 82; A conductor II4 connects conductor H6 and ring 2.

Therefore, when the four sets of contacts 64:- close, they partially condition circuits to the four relay solenoids 66. At rotation of shaft 26, switch 54 closes and completes the conditioning, of these circuits. Now if springs touch one or more of the contactors I6, I8, 80 or 62, they complete the circuit to the corresponding relay solenoid, whereupon contacts 65 and H2 of that relay close. Contacts 65 seal in the circuit to their solenoid, so that this solenoid remains energized after switch 53' opens at 210 rotation of shaft 2|.

It is not necessary for a spring to remain in contact with a contactor I6, I8, 80 or 82 for a solenoid 66 to remain energized, but the solenoid remains energized once the spring has touched the contactor during the period in which the circuit is conditioned (180 to 210 rotation of shaft 2 I If a spring touches a contactor after switch 53 opens, it does not energize a solenoid 66, since the circuit to these solenoids no longer is conditioned. This arrangement eliminates inaccuracies which subsequent spring vibrations might cause.

Closing of a contact II2 conditions a circuit to the corresponding motor I6. This circuit includes conductor II6, contacts II2, a conductor 68, a motor I3, conductors 68' and I24, relay contacts I2 (now open) and conductors I22 and IIS,

At 240 rotation of shaft 2|, switch 55 closes and energizes relay solenoid I0, via conductors II, 63, GI, and 56, whereupon relay contacts I2 close. Closing of these contacts completes the circuit;

to a motor I3 and opens 4, 5, 6 or I.

At 270 rotation of shaft 2I, while the slide is still open, switch 52 opens and de-energizes magthe corresponding slide 1,6, netic thruster 5 I, whereupon valve 58 releases the.-.

escapee air pressure from cylinder 46. The air discharges from this cylinder via pipe 60-, valve '58, pipe-I06, manifold I08, hoses H and spindles 93 and blows any spring which is over an'o'pen'slide through the hole 9 beneath.

At 360 rotation of shaft 2|, switch 55 opens and dc-energizes solenoid 10, whereupon contacts 12 open and break the circuit to motors! 3. of slides 4, 5, 6 or 1 which have been open now close, Shaft commences to rotate and thus another cycle starts. At 372 rotation of shaft 2|, or 12 after the start of the succeeding cycle, switch 54 opens and breaks the circuit to any of solenoids 66 which have been energized.

In operating the classifierabove described the operator places a spring in the bore [9 of one of the embracements l8 during one of the stops in the intermittent motion of the turntable It. This embracement then advances to beneath the top-spring-end depressor 45, this requiring the shaft 21 to rotate through 120. At this time the switch 52 closes, air is admitted to the top of the cylinder 46 and the depressor 45 drives the top* spring-end down into the embracement and seats its bottom end firmly on the upper surface of L insert I64, coextensive with surface -3 of the ring 2. The shaft 2| continues to turnwhile the shaft [5 remains stationary and when the shaft 2| has turned 270 the switch 52 opens and the spring 41 smoothly and evenly returns the depressor to its inoperative position.

At 120rotation of shaft 21, the embracement which carries the spring has moved to a position over slide 4, where it stops. If the spring is' long enough, it touches contactor 16, which causes slide 4 to open and to discharge the spring to drawer 38. If the spring is too short to touch contactor 16, it advances to a position over slide 5, where if it is long enough, it touches contactor 18. This step-by-step advancement continues until the spring touches a contactor, which then opens a slide and discharges the spring to the appropriate drawer. Regardless of which contactors the spring ultimately contacts, the trap door over which it is thenregistered opens, providing the top end of the spring contacted the contactor during the first portions of the stops in registration therewith and not during the latter portions of these stops when the spring had'begun to vibrate. If the spring is too short to touch any of the contactors it ultimately arrives over the hole 42 and it then falls from the em bracement carrying it. As previously explained; the springs are conveyed from'the various trap doors to appropriate collection points;

Having thus fully disclosed a preferred embodiment of the classifying device of the present invention,'I desire to claimas new the following.

I claim: H i

1. A coil spring classifier including a member with a substantially horizontal, smooth, flat top surface having a series of flush trap doors, a plurality of upstanding spring embracements mounted to travel repetitiously over saidtop surface of the member in line with-the series'of'trap doors, the embracements being so constructed and arranged as to hold the springs at right angles to the top surface oi-the member with the bottom ends of the springs supported on the top surface of the member, means for causing said embracements to travel intermittently, with stops While in registration with said trap' doors,- means for gauging .thehe'ight of the springs at each trap door, means associated with each trap door operable in response to the gauging means" above it to open the trap door -when the spring above it is of a predetermined height, a topspring end depressor registered 'abc've an em bracement-stopping position in advance or the series "of trap doors, means for operating said eepresser during -'se3'rd'-stbps-, said depressor operating means including an air "cylinder connected to the depressor, a source of "compressed air, and valve means between the sourceand the cylinder operated timedirelationshipwv'ith the means for causing the embracements to travel to admit to 'the cylin'der to cause the depressor to cantac-t the spring during stop age er tneernbrace merits and later, during the same-stoppage, to e'ir-haust-air -fror'n the cylinder "to withdraw the depressor fro'm eontac't with the spring, and means for assisting removal of springs from the embracements when the trap doors beneath such springs are "open, said last 'lialfid comprising an air Jet positioned above each embrac'enrent above a trap door, said -jet :being directed to discharge -a "stream =0f gas on top of "ea'ch sprirlg in such 'embraeements, and conduits connecting said jets to the discharge port of the valve so "that c'ompres'se'dair discharged from the depressor operating air cylinder is dis'charged through the jets.

2. -A 6611 spring classifier including a member with a Substantially horizontal, Smooth, fiat tap surraee having a Series bf flush trap dbdrsfa piuiality or upstanding spring embracements meu'nted to travel repetitiousiy ever said t0p-slir-- face of the member in lin'e with the series of trap doors, the embracements being so con- Tstructed and arranged as to l' iold the spring at right angles to the to surface or the member with the bottom nds bf the springs supported on the top surfaceof the member, means for causing said embracements 'to travel intermittently, with steps While in registration with said trap doorsa top-spring-end conta-ctor over each trapdoor above the embracement tops at differin'g heights, each of said cdntactors being meanted on a support above the member with-the hot-i"- zcntal top surface by means of an adjustable micrometer mounting, said i-riountin'g -'including an internally threaded barrel mounted on the support andespindle projecting theret-hroug-h and having threaded engagement therewith, the contactor being mounted on the lower end or the spindle, the spindle havin a longitudinal passage therethrough and the contactor'h'av ing a passage therethrough connecting with the passage-through the spindle and emerging "at the lower top-spring-en'd "contacting surface of the conta'c tor, means to supply "compressed gas to the upper end of the passage through the spindle, v-aiveme'ens to allow assageof gas through the spindle nd contactor'to emer e as a stream on a top s'pring-nd in an embraeement beneath the contactera nd above-a trap door, means to operate the valve to discharge gas from the contactor only when an embraeementis beneath the eontacter, means connected to each trap door "selec= tively to open and close the doors, means operated by thetop-spring end -"con't'ac t'or for eecn trap door't'o actuate the trap door, the contactor over which contacted by a topspring end momentarily, to open the door to allow the spring to escape from theembra'cement and to close it thereafter.

A ecu spring classifierin'clud-ih'g a member with a Substantially horizontal, si-neeth, flat top sui -face having series at trap users, 'a lurality er upstanding spring embracements mounted to travel repetitiously over said top surface of the member in line with the series of trap doors, the embracements being so constructed and arranged as to hold the springs at right angles to the top surface of the member with the bottom ends of the springs supported on the top surfac of the member, means for causing said embracements to travel intermittently, with stops while in registration with said trap doors, a top-spring-end contactor over each trap door above the embracement tops at differing heights, each of said contactors being mounted on a support above the member with the horizontal top surface by means of an adjustable micrometer mounting, said mounting including an internally threaded barrel mounted on the support and a spindle projecting therethrough and having threaded engagement therewith, the contactor being mounted on the lower end of the spindle, the contactor having a lower face with a fiat centrally located circular zone located in a plane parallel to the top flat surface of the member and a zone surrounding the central zone in the form of a surface of revolution about the axis of the spindle, th distance from points on the outer zone of the contactor to the top surface of the member decreasing gradually in a direction approaching the central zone of the lower contactor surface, the spindle having a longitudinal passage therethrough and the contactor having a passage therethrough connecting with the passage through the spindle and emerging at the lower top-spring-end contacting surface of the contactor, means to supply compressed gas to the upper end of the passage through the spindle, valve means to allow passage of gas through the spindle and contact-or to emerge as a stream on a top-spring-end in an embracement beneath the contactor and abov a trap door, means to operate the valve to discharge gas from the contactor only when an embracement is beneath the contactor, means connected to each trap door selectively to open and close the doors, and means operated by the top-spring-end contactor for each trap door to actuate the trap door, the contactor over which is contacted by a top-spring-end momentarily, to open the door to allow the spring to escape from the embracement and to close it thereafter.

4. A classifier for coil springs comprising a metal plate having a smooth horizontal surface and containing a plurality of arcuately arranged spring discharge holes, slides normally closing said discharge holes, a rotatably supported turntable above'said plate, a plurality of arcuately arranged spring embracements on said turntable, means for rotating said turntable in stepby-step fashion with embracements stopping in registry with said discharge holes, electric contactors of progressively decreasing height above said discharge holes, motors for operating said slides, and electric means for operating the corresponding motor when a spring which is positioned above a discharge hole touches the contactor above that hole, said electric means includ- 10 ing a relay for each of said motors, a circuit which connects the solenoids of said relays, said contactors and said plate and which is conditioned after said turntable stops, said circuit closing and energizing the corresponding relay when a spring touches a contactor, a first set of contacts in each of said relays which closes when the relay is energized and seals in this relay, a second set of contacts in each of said relays which closes when the relay is energized, a circuit which connects said second sets of relay contacts and said motors, said last named circuit being conditioned for the corresponding motor when any of said second sets of contacts close, and a switch for completingthe circuit to any of said motors while that circuit is conditioned.

5. A classifier for coil springs comprising a metal plate having a smooth horizontal surface and containing a plurality of arcuately arranged spring discharge holes, slides normally closing said discharge holes, a rotatably supported turntable above said plate, a plurality of arcuately arranged spring embracements on said turntable, means for rotating said turntable in step-by-step fashion with embracements stopping in registry with said discharge holes, electric contactors of progressively decreasing height above said discharge holes, motors for operating said slides, and electric means for operating the corresponding motor when a spring which is positioned above a discharge hole touches the contactor above that hole, said electric means including a relay for each of said motors, a circuit which connects the solenoids of said relays, said contactors and said plate and which is conditioned for an interval; after said turntable stops, said circuit closing and, energizing the corresponding relay when a spring; touches a contactor during said interval, a first: set of contacts in each of said relays connected. to the solenoid of that relay and closing when the solenoid is energized for sealing in the relay, a second set of contacts in each of said relays free of connection with the solenoids and closing when the solenoid is energized, a circuit which connects said second sets of relay contacts and said motors, said last named circuit being conditioned for the corresponding motor when any of said second sets of contacts close, and a switch for completing the circuit to any of said motors while that circuit is conditioned.

GEORGE DONALD FEN TON.

. REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 211,975 Dickinson Feb. 4, 1879 279,038 Stillman June 5, 1883 934,730 Jaques Sept. 21, 1909 1,873,315 Dreyer Aug. 23, 1932 1,882,374 Strickland Oct. 11, 1932 1,984,031 Purdy Dec. 11, 1934 2,409,265 Fenton Oct. 15, 1946 

